Article handling system with dispenser

ABSTRACT

In a system for dispensing weighed or counted articles, articles are fed from a supply hopper by a vibratory conveyor to maintain a controlled level of articles in a bowl-shaped feeder hopper. In a weigher embodiment, articles are initially discharged from the feeder hopper through two discharge openings into an accumulator bucket. A weighing unit monitors the weight of articles in the bucket and signals a door to close one of the discharge openings as the weight of articles in the bucket begins to approach a predetermined weight. The weighing unit subsequently signals the feeder hopper drive to slow its feeding action as the weight of articles in the bucket more closely approaches the predetermined weight. The feeder hopper discharge openings are arranged near each other at locations where the door-controlled opening will provide a rapid, bulk feed of articles, while the other opening will provide a single-file trickle feed. In a counter embodiment, a feeder hopper having a single discharge opening is used so that articles can pass single file from the feeder hopper past a counter unit to an accumulator bucket.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of co-pending U.S. patentapplications Ser. Nos. 618,025 and 618,079, filed Sept. 30, 1975 by theinventor of this application, now abandoned.

REFERENCE TO RELEVANT PATENTS AND APPLICATION

"Article Handling System With Weight-Controlled Dispenser", by BernardLerner, Ser. No. 833,260, filed Sept. 14, 1977 as a continuation ofapplication Ser. No. 618,079, filed Sept. 30, 1975 now U.S. Pat. No.4,095,723, issued June 20, 1978.

"Counting System", U.S. Pat. No. 3,584,226, issued June 8, 1971, herethe "Counting Head Patent".

"Article Handling apparatus With Automatic Controls for Supply andDispenser", U.S. Pat. No. 3,610,464 issued Oct. 5, 1971, here the"Dispenser Patent".

"Packaging Method and Apparatus", U.S. Pat. No. 3,815,318 issued June11, 1974, here the "Packaging Machine Patent".

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to material handling apparatus,and more particularly to apparatus for rapidly, accurately andrepetitively dispensing batches of articles of predetermined weight orquantity.

2. Prior Art

Articles are frequently packaged in batches of predetermined weight orquantity. Due to the number and diversity of small articles which arepackaged in batches, apparatus capable of rapidly, accurately, andautomatically dispensing successive batches of articles is in demand.

Previously proposed apparatus for dispensing batches of articles havesuffered one or more of the drawbacks of inadequate operating speed,weighing inaccuracy and/or inconsistency, vibration sensitivity, andlack of versatility in handling differing types of articles and articleweights.

While proposals have been made to use vibratory feeding systems todeliver articles to a weighing or counting apparatus, problems have beenencountered in successfully implementing such proposals. One problem hasbeen that of stopping the feed of articles into the weighing or countingapparatus immediately after a predetermined weight or count of articleshas accumulated. Often some articles have already begun discharging fromthe vibratory feeding equipment into the weigher or counter at the timea desired weight or count of articles has accumulated. In some systems,efforts are made to divert such tardily discharging articles into anoverfeed receptacle from which they are returned to the vibratoryfeeder. There are instances when the tardily discharging articles enterthe weigher or counter and cause the accumulated batch to have anexcessively large weight or count.

Proposals to overcome this problem of weighing or counting inaccuracyattempted to feed articles into an accumulator bucket at an initiallyhigh feed rate to bring the weight or quantity of articles rapidlytoward a desired amount. When the weight or quantity was close to thedesired amount, the feed rate was reduced until the targeted amount wasachieved. Such proposals have achieved some improvements in articlehandling speed and accuracy. An apparatus of this type is described inthe referenced Dispenser Patent. These proposed systems have oftenrequired two or more independently operating feeder systems.

A problem encountered where vibratory feeding equipment is used withweighing and certain counting apparatus has been that the operation ofthe apparatus may be adversely effected by vibrations generated in thefeeding equipment. A counting apparatus which is not subject tovibration-induced error and which can be used in the environment ofvibratory systems is described in the referenced Counting Head Patent.With weighing systems, however, separate, relatively massive vibrationisolating mounting systems have been used to support the feeder and theweighing equipment in an effort to reduce vibration-caused weighingerrors.

Where vibrations are transmitted from vibratory feeding equipment to aweighing apparatus, the time required to weight a quantity of articleshas often had to be extended to assure accuracy. In some weighingsystems, article weight is determined by integrating sensed weight overan interval of time as long as several seconds to improve accuracy. Theextended weighing time requied by such systems necessitatescorrespondingly slow feeder rates and the speed of operation of suchsystems is undesirably slow.

Achieving acceptable operating speeds together with weighing or countingaccuracy is rendered more difficult where the apparatus must be capableof handling a wide range of article sizes, together with a wide range ofarticle accumulation weights or counts. While some prior systems arereasonably effective in handling articles of a given size and weight fordispensing within a given range of article accumulation weights orcounts, these systems are often not well adapted to handle articles ofsignificantly different sizes and weights and/or significantly smalleror larger article accumulation weights or counts.

Another problem with prior apparatuses is that the accumulator bucketsemployed in their weighing or counting systems typically overlie ornearly overlie other supporting or operating components of theapparatus. Stated in other terms, the accumulator buckets ofself-supporting apparatuses which do not have to be anchored to asupporting surface have an inadequate overhang in relation to nearbyapparatus components to permit a direct discharge from such buckets intoconveyors, packaging equipment and the like. Special chutes mustaccordingly be constructed to interface proposed apparatuses with suchreceptacles and other equipment.

SUMMARY OF THE INVENTION

The present invention overcomes the foregoing and other drawbacks of theprior art and provides an apparatus capable of rapidly, accurately,repetitively and automatically dispensing batches of articles.

Articles from a supply hopper are fed to a bowl-shaped feeder hopper tomaintain a controlled level of articles in the feeder hopper. In oneembodiment, in the initial part of a feed cycle, articles are dischargedfrom the feeder hopper through two discharge openings into anaccumulator bucket. A weighing unit monitors the weight of articles inthe bucket and signals a door to close one of the discharge openings asthe weight of articles in the bucket begins to approach a predeterminedweight. The weighing unit subsequently signals the feeder hopper driveto slow its feeding action as the weight of articles in the bucket moreclosely approaches the predetermined weight. Once the predeterminedweight is reached, the feeder hopper drive is stopped and the weighedbatch of articles is discharged from the bucket.

In another embodiment, articles are discharged from the feeder hopperinto an accumulator bucket through a single discharge opening. Acounting unit is positioned immediately adjacent the feeder hopperdischarge station and monitors the quantity of articles fed into thebucket. As the count of accumulated articles approaches a predeterminednumber, the counting unit signals the feeder hopper drive to slow itsfeeding action. Once the predetermined count is reached, the feederhopper drive is stopped and the counted batch of articles is dispensedfrom the bucket.

One feature of the invention is a construction and arrangement ofapparatus components which permits a counting unit to be positionedimmediately adjacent the output station of a vibratory feeder. The closeproximity positioning of the counter minimizes the accumulation of anovercount in batches due to tardily discharging articles which may betraveling in mid-air toward an accumulator bucket before a downstreamcounter senses the completion of a desired count.

One feature of apparatus embodying the present invention is the geometryof its arrangement. A self-supporting apparatus is provided which doesnot need to be anchored to a supporting surface and yet which locatesthe accumulator bucket with a substantial overhand in relationship toother components of the apparatus. The bucket can, by virtue of thisfeature, discharge directly into large containers or conveyors orpackaging apparatus without requiring special chutes or other structureto effect an interface.

The advantageous arrangement of components includes a substantiallyin-line positioning of the supply hopper, the feeder hopper, ahopper-to-hopper vibratory conveyor, and the accumulator bucket. Thesein-line components are supported at a location between the supply hopperand the accumulator bucket such that the bucket is suspended incantilevered fashion. Even though the bucket is suspended incantilevered fashion, this arrangement of components provides acounterbalanced apparatus that is self-supporting and does not have tobe secured to a mounting surface to maintain its stability.

An additional feature resides in a modular construction of the apparatuswhich facilitates servicing and replacement with minimal machine "down"time. The supply hopper, the vibratory conveyor, the feeder hopperdrive, the feeder hopper, the weighing unit, the counting unit and theaccumulator bucket each form separable modules that can be removed andreplaced in minimal "down" time. An advantage of this modularconstruction is that the apparatus of the present invention can easilybe converted from a batch weighing system to a batch counting system orvice versa.

A feature of the apparatus in the weigher embodiment is the provision ofboth lower "bulk feed" and an upper "dribble feed" discharge opening ina single feeder hopper. The feeder hopper is of substantiallyconventional bowl-shape and includes an inclined ramp that spiralsupwardly along the inside of the hopper sidewall toward the upperdischarge opening. The lower discharge opening is formed through thesidewall of the feeder hopper at a location immediately below the upperdischarge opening. The discharge opening is tangential to thecircumference of the bowl.

A power-operated closure system selectively opens and closes the loweropening to permit an initial bulk, discharge of articles from the hopperbowl. Since the lower discharge opening is tangential to the sidewall ofthe bowl, the closure of the lower opening does not distrub the movementof articles in the feeder bowl. Following a bulk discharge of articlesfrom the lower opening, a dribble or trickle feed discharge of articlesis continued from the upper discharge opening. As the weight of articlesin the bucket closely approaches a desired predetermined weight, theoperation of the vibratory feeder is slowed to slow the dribble feedrate. The dribble feed rate is continued until the desired batch weightis obtained, whereupon feeder operation is stopped.

The presence of both bulk and dribble feed discharge systems gives theapparatus of the present invention a degree of versatility not presentin prior proposals. Where only a small quantity of articles is to beaccumulated in each batch, the bulk discharge opening is kept closed andonly the dribble feed discharge system is used. Where each weighed batchis to include a large number of articles, combined operation of the bulkand dribble discharge systems is employed, as described, to provide arapid accumulation of the requisite number of articles for each weighedbatch.

The power-operated closure system associated with the bulk dischargeopening features a door that closes with an upward movement. The upwardclosure movement has been found to be advantageous in preventingarticles from being jammed between the door and portions of the feederhopper which define the bulk discharge opening.

It is important to maintain a controlled level of articles in the feederhopper to assure proper, consistent feedings. This is especially so inthe weigher embodiment since articles are fed at high rates directlyfrom the floor of the feeder hopper through a lower discharge opening,and the level of articles in the feeder hopper can be reduced veryquickly.

Another feature of the present invention lies in a novel level switchassembly used to adjustably set and maintain a controlled level ofargicles in the feeder hopper. The level switch assembly and thecomponents it controls maintain the level in the feeder hoppersubstantially constant.

The level switch assembly includes a counterbalanced, pivotally mountedwiper arm that engages the upper surfaces of articles in the feederhopper. A sensing potentiometer is connected to the wiper arm such thatits resistance varies in response to changes in the level of articles inthe feeder hopper. A manually adjustable reference potentiometerprovides a reference resistance indicative of a desired level to bemaintained in the feeder hopper. Comparison circuitry compares inputsignals from these two potentiometers and provides an output signal toinitiate operation of the hopper conveyor when the level of articles inthe feeder hopper is below the desired level. An indicator light islocated on the level switch housing and lights when a lower than desiredlevel is sensed to assist the operator in setting a desired level on themanually adjustable potentiometer.

Another feature of the invention lies in the provision of alignedclean-out doors on the supply hopper and vibratory conveyor which permitarticles to be conveniently removed from the supply hopper and theconveyor without processing the articles through the vibratory feeder.

Other features of the invention lie in the provision of a weighing unitwhich can be mounted on the same supporting structure with vibratoryfeeding equipment without being adversely affected by vibrations. Theweighing system includes a simple balance beam linkage that supports acoil and the accumulator bucket on opposite ends of a balance beam. Thepower supplied to the coil is controlled to generate such balancingforces as are required to maintain the balance beam in a predeterminedposition. Light from a light-emitting diode is reflected from a movablereference surface connected to the balance beam and is detected by aphotocell to signal when the balance beam has moved from itspredetermined position. The signal from the photocell is used to adjustthe power supplied to the coil to counterbalance the weight of articlesin the accumulator bucket. The weighing unit effectively electronicallydamps any tendency of the accumulator bucket to vibrate, therebypermitting a rapid, nearly instantaneous weighing of articles in thebucket.

It is a general object to provide a novel and improved batch weighing orcounting and dispensing system.

It is another object to provide an improved vibratory feeder with a pairof discharge openings communicating with a single feeder hopper toselectively provide bulk and dribble discharge of articles from thehopper.

These and other objects and a fuller understanding of the invention maybe had by referring to the following description and claims taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of an apparatus embodying thepreferred practice of the invention with some portions of the apparatusbroken away to illustrate the arrangement of other portions;

FIG. 2 is a front elevational view of a portion of the apparatus of FIG.1;

FIGS. 3-5 are enlarged side elevational views of portions of theapparatus of FIG. 1.

FIGS. 6 and 7 are enlarged top and bottom plan views of a feeder hopperemployed in the apparatus of FIG. 1;

FIG. 8 is a sectional view as seen from a plane indicated by a line 8--8in FIG. 6;

FIGS. 9, 10 and 12 are enlarged side elevational views as seen fromplanes indicated by lines 9--9, 10--10, and 12--12 in FIG. 6;

FIG. 11 is a sectional view as seen from a plane indicated by a line11--11 in FIG. 10;

FIG. 13 is an enlarged top plan view of a limit switch assembly employedin the apparatus of FIG. 1;

FIG. 14 is a side elevational view of the assembly of FIG. 13;

FIG. 14a is a schematic electrical circuit diagram of circuitryassociated with the assembly of FIG. 13;

FIG. 15 is an enlarged top plan view of a weighing unit assemblyemployed in the apparatus of FIG. 1 with portions of the assembly beingbroken away;

FIGS. 16, 17 and 18 are sectional views as seen from planes indicated bylines 16--16, 17--17 and 18--18 in FIG. 15;

FIG. 18a is an enlarged view of a portion of the apparatus shown in FIG.16.

FIG. 19 is a schematic electrical circuit diagram of circuitryassociated with the assembly of FIG. 15;

FIG. 20 is a top plan view of a base plate employed in the assembly ofFIG. 15;

FIGS. 21 and 22 are side elevational views of the base plate of FIG. 20;

FIGS. 22a and 22b are top plan views of portions of the assembly shownin FIGS. 15-17;

FIGS. 23 and 24 are side elevational views of an armature employed inthe apparatus of FIG. 15;

FIG. 25 is a top plan view of a weighing bucket assembly employed in theapparatus of FIG. 1;

FIG. 26 is a front elevational view of the assembly shown in FIG. 25;and,

FIG. 27 is an enlarged side elevational view of the assembly of FIG. 25.

FIG. 28 is a side elevational view of an alternative embodiment of theinvention with some portions of the apparatus broken away to illustratethe arrangement of other portions;

FIG. 29 is a front elevational view of a portion of the apparatus ofFIG. 28;

FIGS. 30-32 are enlarged side elevational views of portions of theapparatus of FIG. 1;

FIG. 33 is an enlarged top plan view of a feeder hopper employed in theapparatus of FIG. 1;

FIG. 34 is a side elevational view of the hopper of FIG. 33;

FIGS. 35 and 36 are enlarged side and front elevational views of anaccumulator assembly employed in the apparatus of FIG. 28; and

FIGS. 37 and 38 are enlarged rear and side elevational views of anaccumulator bucket assembly employed in the assembly of FIGS. 35 and 36.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1 and 2, an article handling apparatus embodying thepreferred practice of the present invention is indicated by the numeral100. The apparatus 100 is operable to dispense articles, such as pills,washers, screws, or radishes into a container 102 positioned at aloading station 104. Where the container 102 is a bag connected to apackaging web, the container 102 is preferably supported and positionedat the loading station 104 by a packaging machine of the type describedin the referenced Packaging Machine Patent.

The apparatus 100 includes a base structure 110 which supports a supplyhopper 111, a vibratory conveyor 112, a vibratory feeder 113, and aweighing unit 116. The vibratory feeder 113 includes a feeder hopper114. The weighing unit 116 includes an accumulator bucket 117. Inoperation, articles to be dispensed are loaded into the supply hopper111. The vibratory conveyor 112 feeds articles from the supply hopper111 into the feeder hopper 114. The vibratory feeder 113 feeds articlesfrom the feeder hopper 114 into the accumulator bucket 117. Theoperation of the vibratory conveyor 112 is controlled by a signal from alimit switch assembly 115 to maintain a predetermined level of articlesin the feeder hopper 114. The operation of the vibratory feeder 113 iscontrolled by a signal from the weighing unit 116 to dispense apredetermined quantum of articles into the bucket 117. After therequisite quantum of articles has accumulated in the bucket 117, thearticles are dispensed into the container 102. A control unit 118monitors operation of the weighing unit 116.

The Base Structure 110

The base structure 110 includes a four-legged stand 121 and a frame 122supported atop the stand 122. A horizontal support surface 123 isdefined at the upper end of the stand. Elastomeric leg cushions 124depend from the rame 122 and engage the support surface 123. Acompartment 125 is defined in one side of the stand 121 to support thecontrol unit 118. In installations where it is necessary to position theapparatus 100 on an existing table or other suitable support, the stand121 can be removed and the control unit 118 positioned beside the frame122 on a table or other support.

Referring to FIGS. 1-3, the frame 122 is a welded assembly including apair of side members 131, 132 which extend upwardly from a bottom plate133. The side members 131, 132 are inclined and extend rearwardly(leftwardly as viewed in FIG. 3) as they extend upwardly. A pair ofbracing plates 134, 135 are welded to inside surfaces of the sidemembers 131, 132 and extend forwardly near the upper ends of the sidemembers 131, 132. A relatively thin hopper support plate 136 is weldedto the side members 131, 132 and to the bracing plates 134, 135 nearrearward ends of the bracing plates. A relatively thick feeder supportplate 137 is welded to the bracing plates 134, 135 near forward ends ofthe bracing plates. A hole, not shown, is formed through the centralregion of the hopper support plate 136 to permit portions of the supplyhopper 111 to extend through the plate 136. Mounting holes 139 areformed through the feeder support plate 137.

Forward and rearward pairs of mounting brackets 145, 146 are welded oninner surfaces of the bracing plates 134, 135. Inwardly turned flanges147, 148 are formed near the lower ends of the mounting brackets 145,146.

The Supply Hopper 111

Referring to FIGS. 1, 2 and 4, the supply hopper 111 has inclinedforward and rearward walls 151, 152 interconnected by side walls 153,154. The side walls 153, 154 have horizontally extending portions 155which overlie portions of the hopper support plate 136. Elastomericmounts 157 are interposed between these side wall portions 155 and thehopper support plate 136 to resiliently mount the supply hopper 111 onthe frame 110.

The supply hopper 111 operates in the manner of a funnel to feedarticles into the vibratory conveyor 112. The top of the hopper 111 isopen to receive articles. The bottom of the hopper 111 is open todeliver articles into the vibratory conveyor 112. An adjustable gate 158is carried on the forward wall 151 and depends to an adjustable depthinto the conveyor 112 to regulate the flow of articles forwardly alongthe conveyor 112. Threaded fasteners 159 having wing heads adjustablyposition the gate 158.

An access door 160 is provided near the lower end of the rearward hopperwall 152. A hinge 161 pivotally mounts the door 160 permitting it toswing upwardly to an open position shown in phantom in FIG. 4. A pair oflatching arms 162 are riveted to the side walls 153, 154 and operate toreleasably retain the door 160 in the closed position shown in FIG. 4.

The Vibratory Conveyor 112

Referring to FIGS. 1, 2 and 5, the vibratory conveyor 112 includes amovably supported trough 171. The trough 171 has a pair of side walls173, and a bottom wall 174. Forward and rearward mounting brackets 175,176 are welded to the underside of the bottom wall 174. Forward andrearward elastomeric spacers 177, 178 are interposed between themounting bracket flanges 147, 148 and the mounting brackets 175, 176 toresiliently mount the trough 171 on the frame 122.

A conventional pneumatically powered vibratory motor 180 is provided tocyclically drive the trough 171 and thereby moves articles forwardly,from left and right as viewed in FIG. 5, along the trough 171. Avibrator mounting bracket 181 is welded to the bottom wall 174. Threadedfasteners 182 secure the vibratory motor 180 to the bracket 181.

An access door 185 is provided at the rear end of the trough 171. Ahinge 186 pivotally mounts the door 185 permitting it to swingdownwardly to an open position shown in phantom in FIG. 5. A pair oflatching arms 187 are riveted to the sidewalls 173 and operate toreleasably retain the door 185 in the closed position shown in FIG. 5.

When the doors 160, 185 are both opened, access can be had to the bottomregion of the hopper 111 and to the rearward region of the trough 171 topermit an operator to clean articles out of the hopper 111 and out ofthe conveyor 112. Without the provision of the doors 160, 185, articlescould only be cleaned out of these regions by processing them throughthe remainder of the apparatus 100.

The Vibratory Feeder 113

Referring to FIGS. 1 and 3, the vibratory feeder 113 includes a motordrive assembly 201. The drive assembly 201 has a housing 202 whichencloses a conventional vibratory motor, not shown. Threaded fasteners203 extend through resilient damper bushings 204 and through themounting holes 139 to mount the housing 202 on the underside of thefeeder support plate 137. An armature 205 depends below the housing 202for connection to the feeder hopper 114. The motor drive assembly 201 isoperable, when energized, to vibrate the armature 205 at a60-cycle-per-second frequency in response to a 60-cycle electrical powersupply. The amplitude of armature vibration is determined by themagnitude of the power supplied to the vibratory motor. The speed atwhich articles are fed by the feeder hooper 114 increases and decreaseswith increases and decreases in the vibration amplitude of the armature205.

The Feeder Hopper 114

Referring to FIGS. 6 and 8, the feeder hopper 114 is a round, bowl-likestructure having a bottom wall 211 and an upstanding side wall 212. Anannular rib 213 projects upwardly into the hopper 114 from the bottomwall 211. Three bolt holes 214 are formed through the rib 213. Threadedfasteners, not shown, extend through the holes 214 and mount the feederhopper 114 on the armature 205.

The hopper side wall 212 forms a spiral ramp 221 that extendscircumferentially inside the hopper 114. The ramp 221 has a lower end222 that extends in the same plane as the bottom wall 211. From thelower end 222, the ramp 221 extends upwardly at a small, uniform angleof inclination to an upper end 223. When the feeder armature 205 isvibrated, the articles in the feeder hopper 114 will move upwardly alongthe ramp 221 from the lower end 222 toward the upper end 223.

Referring to FIG. 8, a discharge station 300 is defined by upper andlower discharge openings 225, 226. The openings 225, 226 are formedthrough the hopper side wall 212 for discharging articles from thehopper 114 into the accumulator bucket 117. The upper discharge opening225 is formed through the floor of the ramp 221 near the upper ramp end223. The lower discharge opening 226 is formed through an upstandingportion of the side wall 212 adjacent the bottom wall 211. The openings225, 226 are separated from each other by only a narrow segment 227 ofthe side wall 212. The upper opening 225 remains open at all times todischarge articles moving along the ramp 221 toward the upper ramp end223. The lower discharge opening 226 is selectively opened and closed bya closure assembly 240.

Referring to FIGS. 6-9, the closure assembly 240 includes a door 241supported for vertical movement at a location outside the hopper 114. Amounting plate 242 underlies the feeder hopper 114 and is secured to thebottom wall 211 and through a slot 264 formed in the mounting plate 242.A pair of lock nuts 265 are threaded onto the lower end of the pistonrod 262 and serve to couple the piston rod 262 to the mounting plate242. When the piston rod 262 extends from the housing 261 in response toa supply of pressurized fluid to the cylinder 260, the mounting plate242 is moved downwardly causing the door 241 to open the lower dischargeopening 226. When the piston rod 262 retracts toward the position shownin FIG. 8, the mounting plate 242 and the door 241 move upwardly to aposition where the door 241 closes the lower discharge opening 226.

Two flow control devices are provided inside the feeder hopper 114 torestrict the flow of articles along the ramp 211 upstream from the lowerdischarge opening 226. Referring to FIG. 6, one of the flow controldevices is indicated by the numeral 280 and defines a ramp section ofcontrolled width to limit the width of a stream of articles flowingtoward the upper opening 225. The other of the flow control devices isindicated by the numeral 290 and operates to limit the depth of a streamof articles flowing toward the upper opening 225.

Referring to FIGS. 6, 10 and 11, the flow restrictor 280 includes amovable gating plate 281 which can be positioned to selectively increaseor decrease the width of the ramp 221 in the region of the assembly 280.The gating plate 281 extends through a slot 282 formed in hopper 114 bythreaded fasteners 243. A pair of hinges 244 connect the forward end ofthe mounting plate 242 to the lower end of the door 241. The hinges 244carry springs 245 which bias the door 241 counterclockwise, as viewed inFIG. 8, into engagement with such portions of the side wall 212 assurround the lower discharge opening 226.

Referring to FIG. 8, a biasing plate 251 underlies rearward portions ofthe mounting plate 242 and is clamped into engagement with the mountingplate 242 by the fasteners 243. The biasing plate 251 biases themounting plate 242 and the door 241 upwardly toward a position where thedoor 241 closes the lower discharge opening 226.

Downward movement of the mounting plate 242 and the door 241 is limitedby a stop bolt 252. The stop bolt 252 extends through a slot 253 formedin the mounting plate 242 and is threaded into a hole 254 formed in thebottom wall 211. A resilient washer 255 is carried near the head of thebolt 252. The resilient washer 255 engages the mounting plate 242 whenthe mounting plate 242 is in its lowermost position where the door 241opens the lower discharge opening 226.

A fluid-operated cylinder 260 is provided to open and close the door241. The cylinder 260 has a cylindrical housing 261 and an extensiblepiston rod 262. A hole 263 is formed in the rib 213 to receive and mountthe lower end of the housing 261. The piston rod 262 depends through thethe hopper side wall 212. The gating plate 281 has a curved inner end283. The position of the curved inner end 283 determines the effectivewidth of the ramp 221 provided by the gating plate 281. A narrower rampwidth, as provided by the plate 281, will permit a lesser number ofarticles to flow toward the upper discharge opening 225 than will awider ramp width.

Referring to FIG. 10, an L-shaped clamping arm 285 is provided to holdthe gating plate 281 in position. A threaded fastener 286 extendsloosely through a hole formed in the arm 285 and is threaded into thehopper side wall 212 to pivotally mount the clamping arm 285 on thehopper 114. A knurled thumb screw 287 is threaded through a hole 288formed in the hopper side wall 212 and engages the lower leg of theL-shaped clamping arm 285. The upper leg of the clamping arm 285 isbiased by the thumb screw 287 into engagement with the underside of thegating plate 281. The gating plate 281 is easily repositioned in theslot 282 once the thumb screw 287 has been loosened to relieve theclamping action of the arm 285.

Referring to FIGS. 6 and 12, the flow depth regulator assembly 290includes a wiper member 291 which is movably supported on the hopperside wall 212 at a position downstream from the flow restrictionassembly 280 to limit the depth of the flow of articles along the ramp221. The wiper member 291 extends inwardly from the side wall 212 andoperates to deflect an excessive flow of articles back onto the bottomwall of the hopper 114.

A threaded fastener 292 has its head secured to the wiper member 291. Athreaded stem of the fastener 292 extends through a slot 293 formed inthe hopper side wall 212 and is received in a knurled nut 294. When thenut 294 is loosened, the fastener 292 can be moved upwardly ordownwardly in the slot 293 to position the wiper member 291. Once thewiper member 291 is positioned to properly limit the depth of flow ofarticles along the ramp 221, the nut 294 is tightened to secure thewiper member 291 in position.

The Level Switch Assembly 115

Referring to FIGS. 2, 13 and 14, the level switch assembly 115 includesa generally rectangular housing 301 and a paddle assembly 302 whichdepends into the feeder hopper 114 (or feeder hopper 914, FIGS. 29, 33,and 34). A bracket, not shown, supports the housing 301 on the frameside plate 135.

The housing 301 includes a casing 303 and a cover plate 304. Threadedfasteners 305 secure the cover plate 304 on the casing 303. Four holes311, 312, 313, 314 are formed through sidewalls of the housing 301. Aresilient grommet 315 is positioned in the hole 311 and guides amulti-conductor electrical cable 316 through one sidewall of the housing301. A socket assembly 317 is supported in the hole 312 and includes alight generating element 318 viewable from outside the housing 301.

A pair of potentiometers 321, 322 are mounted inside the casing 303. Thepotentiometers 321, 322 have rotatable stems 323, 324 which extendthrough the holes 313, 314. A rotatable known 325 is mounted on the stem323 of the potentiometer 321. A paddle mounting bracket 326 is mountedon the stem 324 of the potentiometer 322. A set screw 327 secures thebracket 326 to the stem 324. A hole 328 is formed through the bracket326.

The paddle assembly 302 includes an elongated paddle support rod 329.The rod 329 extends through the bracket hole 328 and has upper and lowerend regions 330, 331. A balance weight 332 is carried on the upper endregion 330. A set screw 333 secures the weight 332 in place on the rod329. A wiper blade 334 is riveted to the lower end region 331. The wiperblade 334 has a rounded end region 334a and is configured to provideminimal obstruction to articles passing beneath it along the bottom wall211 of the feeder hopper 114 in directions indicated by arrows 335.

The balance weight 332 is positioned on the rod 329 at a location wherethe weight of the lower end region 331 is largely counterbalanced. Theweight 332 is positioned such that the wiper blade 334 is biased verygently by the weight of the lower end region 331 into engagement withupper surfaces of articles moving in directions indicated by the arrows335. The balance arm assembly 302 is, therefore, positioned, by virtueof the engagement of the wiper blade 334 with articles in the feederhopper 114, in an attitude indicative of the level of articles in thehopper 114. The resistance of the potentiometer 322 varies as a functionof the actual level of articles in the hopper 114.

Referring to FIG. 14a, the potentiometer 321 produces a reference signalon a lead 337 as a function of the position of the knob 325. Thisreference signal is indicative of the desired level of articles in thefeeder hopper 114. The potentiometer 322 produces a voltage signal on alead 338 indicative of the actual level of articles in the feeder hopper114.

The reference signal on the lead 337 is transmitted through a resistor339 to the inverting input of an operational amplifier 340. The levelsignal on the lead 338 is transmitted through a resistor 341 to thenoninverting input of the operational amplifier 340.

The amplifier 340 compares the reference signal and the sensed levelsignal and provides an output signal on a lead 342. The output signal onthe lead 342 is relatively high when the sensed level signal on the lead338 is greater than the reference signal on the lead 337. The outputsignal on the lead 342 is relatively low when the sensed level signal onthe lead 338 is less than the reference signal on the lead 337.

The output signal on the lead 342 is used to control the operation ofthe vibratory conveyor motor 180 and to energize the light generatingelement 318. The light generating element 318 is a light emitting diodeconnected as shown in FIG. 14a to light only when the output of theamplifier 340 is relatively high to indicate a condition where theactual level of articles in the feeder hopper 114 is below the desiredreference level. The vibratory conveyor motor 180 is energizedconcurrently with the lighting of the element 318, and is de-energizedconcurrently with the element 318 when the sensed actual level ofarticles in the feeder hopper is at or above the predetermined referencelevel.

The multi-conductor cable 316 supplies power to the circuitry shown inFIG. 14a and transmits the output signal on the lead 342 to a suitableconventional controller, not shown, for operating the conveyor drivemotor 180.

The Weighing Unit 116

Referring to FIG. 3, a weighing unit support bracket 360 is mounted atopthe feeder support plate 137. The bracket 360 extends forwardly of thesupport plate 137 and supports the weighing unit 116.

Referring to FIGS. 1, 15-17, the weighing unit 116 includes a weightresponsive singalling system 370 supported in a housing assembly 371.The signalling system 370 includes an armature 372. The accumulatorbucket 117 is connected to and supported by the armature 372, as will beexplained. As articles are discharged from the feeder hopper 114 intothe accumulator bucket 117, the weight of such articles increases thedownward force applied by the accumulator bucket 117 to the armature372. The signalling system 370 senses the increase in force applied tothe armature 372 and provides an output signal representative of theweight of articles in the accumulator bucket 117.

The housing assembly 371 includes a downwardly opening cover structure373 which is bolted to the support bracket 360. The housing assembly 371additionally includes a base structure 374 which closes the bottom ofthe cover structure ture 373 and supports the components of thesignalling system 370. Threaded fasteners 375 connect the base structure374 and the cover structure 373.

A closed chamber 380 is defined inside the housing assembly 371. Abreather hole 381 is formed through the top wall of the cover structure373. A breather fitting 382 is threaded into the hole 381 to assure thatair pressure in the chamber 380 equals ambient air pressure. Aconnection opening 385 is formed through the base structure 374. Aflexible diaphragm 386 is positioned across and closes the opening 385.A clamping ring 387 perimetrically clamps the diaphragm 386 against suchportions of the base structure 374 as surround the opening 385. Threadedfasteners 388 extend through holes formed in the clamping ring 387 andare threaded into aligned holes formed in the base structure 374.

Referring to FIG. 17, a threaded vertically extending hole 399 is formedin the base structure 374 near the connection opening 385. The diaphragm386 and the clamping ring 387 close the lower end of the hole 399.

Referring to FIGS. 20-21, the base structure 374 has several formationswhich project upwardly into the chamber 380. One of these formations isa projection 401 which will be referred to as a sensor mountingprojection. Another of the formations is a projection 402 which will becalled the magnet mounting projection. Still another formation is aU-shaped projection 403 which is called the balance beam mountingprojection.

The sensor mounting projection 401 has a machined, vertically extendingmounting surface 410. A threaded hole 411 is formed through theprojection 401 and extends in a direction perpendicular to the plane ofthe mounting surface 410.

Referring to FIGS. 15, 16, and 18a, a sensor 415 is mounted on thesensor mounting projection 401. A threaded fastener 416 extends througha mounting hole formed in the sensor 415 and is threaded into the hole411 to clamp the sensor 415 into firm engagement with the mountingsurface 410. In preferred practice, the sensor 415 is a self containedunit including a light emitting diode and a photo transistor. The diodein the sensor 415 is arranged to emit a beam of light as indicated by anarrow 417 in FIG. 18a. The photo transistor in the sensor 415 isarranged to provide a variation in an output signal in response toincident light traveling in a direction indicated by an arrow 418 inFIG. 18a. Such sensors are commercially available, one being sold underthe designation SPX-1160-1 by Spectronics, Inc., Richardson, Texas,75080.

Referring to FIGS. 20-22, the magnet mounting projection 402 defines around, horizontally extending mounting surface 430. Referring to FIG.16, an annular permanent magnet 431 is mounted atop the surface 430. Ahole 432 is formed centrally in the magnet 431.

Referring again to FIGS. 20-22, the balance beam mounting projection 403has two spaced mounting portions 440, 441. Aligned holes 442, 443 areformed through the portions 440, 441. Threaded holes 444, 445 are formedin the portions 440, 441 and intersect the holes 442, 443. Referring toFIG. 16, a balance beam pivot rod 446 extends through the holes 442,443. Set screws, not shown, are threaded into the holes 444, 445 to holdthe pivot rod 446 in place on the base structure 374.

Referring to FIG. 22, an upwardly facing machined recess 460 is formedin the base structure 374. Two threaded holes 461 are formed in the basestructure 374 and open into the recess 460. A cast depression 462 isprovided between the threaded holes 461. Referring to FIG. 16, a pivotblock 463 is positioned in the recess 460. Threaded fasteners 464 extendthrough holes formed in the pivot block 463 and are threaded into theholes 461.

Referring to FIG. 22a, the pivot block 463 has a centrally locatedrecess 470 which aligns with the cast depression 462 formed in the basestructure 374. A pair of aligned holes 471 are formed in portions of thepivot block 463 which border on opposite sides of the recess 470. A pairof threaded holes 472 intersect the aligned holes 471. Referring to FIG.16, a pivot pin 473 extends through the holes 471. Set screws, notshown, are threaded into the holes 472 to hold the pivot pin 473 inposition on the pivot block 463.

Referring to FIGS. 15-17, a balance beam 501 is pivotally mounted on thepivot rod 446. The balance beam 501 is a relatively thick metal platewhich extends substantially horizontally through upper portions of thechamber 380. A pair of bearing blocks 502 are secured by threadedfasteners 503 to the forward end region of the balance beam 501. A pairof precision bearings 504 are carried by the bearing blocks 502 andjournal opposite ends of the pivot rod 446 to pivotally mount thebalance beam 501 on the base structure 374.

Four components are carried by the balance beam 501. As will beexplained in greater detail, the armature 372 is pivotally mounted nearthe forward end of the beam 501. A plurality of weights 520, anelectromagnetic coil 530, and an L-shaped target member 540 are rigidlymounted on rearward portions of the beam 501.

Referring to FIGS. 15 and 16, the wieghts 520 are rectangular leadplates which assist in counterbalancing the load applied to the armatureby the dead weight of the accumulation bucket 117. Threaded fasteners521 extend through aligned holes formed in the weight plates 520 and arethreaded into the balance beam 501 to securely mount the weight plateson the balance beam 501.

The electromagnetic coil 530 is a cylindrical assembly ofconventional-design and is purchased commerically. A hole 531 is formedthrough the balance beam 501 to receive an upper end of the coilassembly 530. Suitable fasteners, not shown, securely fasten the coil530 to the balance beam 501. A pair of electrical terminals 532 arecarried on the beam and connect electrically with opposite ends ofconductors which connect with the electromagnetic coil 530. Suitableconductors couple the terminals 532 to circuitry shown in FIG. 19, aswill be explained.

Referring to FIGS. 16, 18 and 18a, the L-shaped target member 540 is aprecision machined component having a horizontally extending surface 550positioned in a plane which preferably includes the point ofintersection of the arrows 417, 418. A rearwardly facing reflectionsurface 551 intersects the surface 550 along a line which preferablyincludes the point of intersection of the arrows 417, 418. A slot 522 isformed through the upstanding leg of the target member 540. A threadedfastener 553 extends through the slot 552 and rigidly mounts the targetmember 540 on the balance beam 501.

Referring to FIGS. 23 and 24, the armature 372 is a generally Y-shapedstructure having a pair of spaced upwardly extending arms 570, 571 and acentral stem 572 terminating in a lower end region 573. Aligned holes574, 575 are formed through the arms 570, 571. A pair of threaded holes576, 577 are formed in the arms 570, 571 and intersect the holes 574,575. Referring to FIGS. 16 and 17, a pivot rod 580 extends through theholes 574, 575 and through aligned holes in the bearing block 502. Setscrews 582, 583 are threaded into the holes 576, 577 and securelyconnect the pivot rod 580 to the armature 372. Precision bearings 584,585 are carried by the bearing blocks 502, 503 and journal opposite endsof the pivot rod 580 to pivotally support the armature 372 on thebalance beam 501.

Referring to FIGS. 23 and 24, the stem 572 of the armature 372 has apair of spaced side portions 600, 601 which border opposite sides of agenerally rectangular hole 603. An upper portion 604 borders the upperside of the hole 603. The lower portion 573 borders the bottom side ofthe hole 603. A pair of threaded holes 607, 608 are formed in the sideportions 600, 601. A hole 609 having a threaded lower end region 610 isformed in the upper portion 604.

Referring to FIGS. 16 and 17, a yoke block 610 extends across the hole603 and overlies the side portions 600, 601. A pair of slots 611, 612are formed through the yoke block 610. Threaded fasteners 613, 614extend through te slots 611, 612 and are threaded into the holes 607,608 to rigidly mount the yoke block 610 on the armature 372. A set screw615 is threaded into the hole 610 and engages an upper surface on theyoke block 610 to assist in positioning the yoke block 610 on thearmature 372.

Referring to FIG. 22b, the yoke block 610 has a pair of spaced,rearwardly projecting arms 621, 622. Aligned holes 623, 624 are formedthrough the arms 621, 622. Threaded holes 625, 626 are formed in theyoke block 610 and intersect the holes 623, 624. Referring to FIG. 16, apivot pin 633 extends through the holes 623, 624. Set screws, not shownare threaded into the holes 625, 626 and securely connect the pivot pin633 to the yoke block 610.

Referring to FIG. 16, an elongated link 640 is pivotally mounted on thepivot pins 473, 633 and interconnects the pivot block 463 and the yokeblock 610. The link 640 carries a pair of bearings 641, 642 whichjournal the pins 473, 633. The rearward end of the link 640 fits looselyin the aligned recess and depression 470, 462. The link 640 serves toguide the movement of the armature 372.

Referring to FIGS. 23, 24, a forwardly facing machined recess 650 isformed in the upper portion 604. A threaded hole 651 is formed in theupper portion 604 and opens into the recess 650. Referring to FIGS. 16,17, a stop block 652 is positioned in the recess 650. A threadedfastener 653 extends through a hole formed in the stop block 652 and isthreaded into the hole 651 to rigidly mount the stop block 652 on thearmature 372. A vertically extending hole 654 is formed through the stopblock 652. The hole 654 overlies the threaded hole 399 formed in thebase structure 374.

A threaded rod 660 extends loosely through the hole 654 and is threadedinto the hole 399. A lock nut 661 is threaded on to the rod 660 and istightened into engagement with the base structure 374 to securelyconnect the threaded rod to the base structure 374. Upper and lowerpairs of lock nuts 664, 665 are threaded onto the rod 660 on oppositesides of the stop block 652. The nuts 664, 665 operate as stops to limitthe vertical travel of the armature 372. The range of vertical movementpermitted by the stop nuts 664, 665 for the travel of the coil 530 isabout one-eighth to three-sixteenths of an inch. When the weighing unit116 is operating, however, the coil, in actuality, does not move morethan about one one-thousandth of an inch.

Referring to FIGS. 23, 24, the lower end region 573 of the armaturedefines a flat, horizontally extending mounting surface 670. Fourthreaded holes 671 are formed in the lower end region 573 and openthrough the mounting surface 670. Referring to FIG. 16, aligned holes672 are formed through the diaphragm. As will be explained, fastenersextend through the diaphragm holes 672 and are threaded into thearmature holes 671 to mount the accumulator bucket 117 on the armature372.

Referring to FIG. 19, circuitry embodying the signaling system 370includes the sensor 415 and the electromagnetic coil 530. The signalingsystem 370 operates to provide a current to the coil 530 to maintain thearmature 372 at a predetermined target level as articles accumulate inthe bucket 117. The signaling system 370 does this by sensing theposition of the armature 372 and by adjusting the current in the coil530 to maintain the armature 372 at the target level. The signalingsystem 370 also senses the amount of coil current required to effectarmature positioning. The required current is a function of the weightof articles in the bucket 117. This current is converted to an outputsignal indicating the weight of articles in the bucket 117.

The sensor 415 produces a signal indicating the deviation of thearmature 372 from the target level. It does this by sensing resistancevariations in the photoresistor of the sensor 415. These variations arecaused by changes in the amount of light which originates in thelight-emitting diode and which is reflected by the surface 551 towardthe photoresistor of the sensor 415. The target element 540 ispositioned by the balance beam 501 such that light from the diode of thesensor 415 impinges on the photoresistor of the sensor 415 when thearmature 372 is located at or near its target level.

Referring to FIG. 18a a knife edge formed at the juncture of the targetsurfaces 550, 551 is positioned at the juncture of the arrows 417, 418when the armature 372 is at its target level. If the armature 372 movesupwardly, the target element 540 moves downwardly presenting less of thereflecting surface 551 to reflect a lesser quantity of light indirections indicated by the arrow 418 toward the sensor 415. If thearmature 372 moves downwardly, the target element 540 moves upwardlypresenting more of the reflecting surface 551 to reflect a largerquantity of light in directions indicated by the arrow 418 toward thesensor 415. These variations in quantity of reflected light received bythe sensor 415 produce corresponding variations in resistance in thesensor 415 and cause the sensor 415 to produce an output signal thatrepresents the position of the armature 372.

The sensor 415 can accordingly be said to serve the function ofindicating to the remainder of the signaling circuitry 370 the fact thatdeviations in armature positioning have occurred and current changes inthe coil 530 are required to restore the armature to its predeterminedlevel. By changing the current flowing through the coil 530, themagnetic force exerted by the coil 530 on the balance beam 501 is alsochanged causing the balance beam 501 to pivot as required to repositionthe armature at its predetermined level.

The signaling circuitry 370 includes a delay damping system forrendering an output signal from the circuit relatively insensitive tominute changes in force exerted on the armature 372 resulting from theimpact of individual product articles dropping into the bucket 117. Thecircuit also contains filtration circuitry for negating the electricaleffect of mechanical vibrations on the bucket caused by nearby vibratoryfeeding equipment and the like.

Referring to FIG. 19, the sensing circuitry includes a voltage followeramplification section 702 connected to receive an output signal from thesensor 415, a delay damping amplification section 704, and transistordrive circuitry 706 for producing an output current to the coil 530. Thecurrent through the coil 530 is measured precisely by a measuringresistor 710. The measured signal is passed through an active filtrationsystem 712 to filter out the electrical effects of mechanical vibrationstransmitted to the armature 372 by surrounding feeding equipment and thelike. The filtered output is presented across a pair of terminals 714.The signal appearing at the terminal 714 has a value which is anaccurate function of the weight of articles which have accumulated inthe bucket 117.

The amplification section 702 includes an operational amplifier 716connected to receive the output from the sensor 415 at a non-invertinginput terminal. The output from the amplifier 716 is impressed on thedelayed damping amplification section 704 by means of a lead 720extending to an inverting input terminal of an operational amplifier722. The amplification section 704 includes a negative feedback loopbetween the output and the inverting input of the amplifier 722incorporating delay circuitry. The feedback loop includes a capacitor724, a resistor 726, and an operational amplifier 730. The output of theamplifier 722 is directed to the transistor drive circuitry 706. Thetransistor drive circuitry 706 includes a set of power transistors 732,734, 736 and 738. The transistor drive circuitry 706 amplifies theoutput signal from the amplifier 722 and transmits this signal to aterminal 740.

The output from the terminal 740 is directed through the seriesconnected capacitor 724 and resistor 726, to a non-inverting inputterminal 742 of the amplifier 730. The output of the amplifier 730 isdirected onto the lead 720, which, as mentioned above, transmits thissignal to the inverting input terminal of the amplifier 722. The effectof the delay feedback capacitor 724 renders the output of the amplifier722 relatively insensitive to small, rapid variations in the signal fromthe sensor 415 caused by the impact of articles dropping into the bucket117.

The signal appearing at the terminal 740 is connected to actuate thecoil 530 to move the armature 372 toward a level approximating thepredetermined level established by the arrangement of the target element540 and the sensor 415. The signal appearing on the terminal 740 isdirected through the coil 530 and subsequently proceeds by way of twoseries connected resistors 746, 748 to an input of the active filtrationsection 712. The precision resistor 710 is connected to the lowerterminal 750 of the coil 530 to receive a major portion of the currentthrough the coil, and to indicate the magnitude of that current by thevoltage appearing at the terminal 752. This voltage precisely indicatesthe amount of current flowing through the coil 530 and is then appliedto the active filtration section 712.

The active filtration system 712 includes two operational amplifiers760, 762 connected to produce an output at the terminal 714. This outputis a function of the voltage appearing at the terminal 752 and which hasbeen filtered free of variations resulting from relatively highfrequency mechanical vibrations in the system. The signal from theright-hand terminal of the resistor 748 is directed to the non-invertinginput of the amplifier 760. The output of the amplifier 760 is directedthrough resistors 764, 766 to the non-inverting input terminal of theoperational amplifier 762. The output from the operational amplifier 762is then directed to the ungrounded one of the terminals 714. As shown inFIG. 19, the filtration section 712 represents an active, low passfiltration circuit having a pass band extending between approximatelytwelve and fifteen Hz.

Circuitry is also provided to calibrate the voltage appearing at theterminal 752, indicating coil current, to correct for variations incircuit element values, imprecision, drift, etc. This function isperformed by a potentiometer 770, connected between ground and theintersection between the resistors 746, 748. In practice, thepotentiometer 770 is adjusted, with the bucket 117 empty, to provide adesired "zero" reading on the output signal appearing at the terminals714.

The Accumulator Bucket 117

Referring to FIGS. 25, 26, the accumulator bucket 117 includes a hangerassembly 801. The hanger assembly 801 includes an upper mounting member802. An upstanding formation 803 is provided at a central location onthe mounting member 802. A flat, upwardly facing mounting surface 804 isprovided atop the formation 803. Four holes 805 extend through theformation 803 and open through the mounting surface 804. Four threadedfasteners 806 extend through the holes 805.

Referring to FIG. 16, the fasteners 806 extend through diaphragm holes672 and are threaded into the armature holes 671. The fasteners 806 aretightened to clamp the diaphragm 386 between the mounting surfaces 670,804 and rigidly mount the bucket 117 on the armature 372.

Referring to FIG. 26, threaded holes 809, 810 are formed in oppositeends of the member 802. A pair of upstanding support arms 811, 812 havetheir upper ends positioned in engagement with the ends of the member802. Threaded fasteners 813, 814 extend through holes formed in the arms811, 812 and are threaded into the holes 809, 810 to securely connectthe arms 811, 812 and the mounting member 802.

Referring to FIGS. 25-27, a receptacle 820 is supported by the arms 811,812. Threaded fasteners 821, 822 extend through aligned holes formed inthe arms 811, 812 and formed in opposite sides of the receptacle 820 tosupport the receptacle 820 on the arms 811, 812.

The receptacle 820 has a front wall 831 and inclined bottom walls 832,833 which define the sides and bottom of a discharge opening 834. Aclosure assembly 840 is provided to selectively open and close thedischarge opening 834.

The closure assembly 840 includes a door 841, a pivot pin 842 whichpivotally mounts the door on the receptacle 820, and a power operatedactuator assembly 843 for opening and closing the door 841. A torsioncoil spring 844 is carried on the pivot pin 842 and biases the door 841toward a position where the door 841 closes the opening 834.

The actuator assembly 843 includes a bracket assembly 844 on the forwardside of the receptacle 820, and a bracket assembly 854 on the rearwardside of the receptacle 820. Threaded fasteners 845, 855 mount thebracket assemblies 844, 854 on the receptacle 820. A door actuator shaft860 has its opposite ends journaled by the bracket assemblies 844, 854.A door engaging arm 861 is rigidly connected to the shaft 860 andoperates to hold the door 841 closed when the shaft 860 is in theposition shown in FIGS. 25-27. A shaft positioning lever 863 is securedto the forward end of the shaft 860.

A pneumatic cylinder 870 connects with the bracket assembly 844 and withthe positioning lever 863 to rotate the shaft 860 and selectively permitthe door 841 to open, or to close. The cylinder has a housing 871, oneend of which is pivotally connected to the bracket assembly 844 by athreaded fastener 872. An extensible piston 873 projects from theopposite end of the housing 871 and is pivotally connected by a yokeassembly 874 to the lever 863. When the piston rod 873 extends from thecylinder housing 871, as when pressurized air is supplied to thecylinder 870, the shaft 860 is rotated to a position where the arm 861will permit the door 841 to open. If articles are present in thereceptacle 820, gravitational forces acting on such articles will causethe door 841 to open to permit the articles to discharge through theopening 834.

The Control Unit 118

The control unit 118 is of the general type described in the referencedDispenser Patent and governs the operation of the vibratory feeder 113in response to a signal from the weighing unit circuitry 370. Inoperation, the control unit 118 causes the bulk discharge door 241 toopen at the initiation of a feeding operation to rapidly deliverarticles into the bucket 117. The control unit 118 causes the door 241to close when the weight of articles in the bucket 117 begins toapproach a predetermined level which has been set on the control unit118. When the sensed weight of articles in the bucket 117 more closelyapproaches the predetermined weight, the control unit 118 slows thefeeding action of the feeder 113. When the weight sensed by thesignalling unit 370 equals the predetermined weight the control unit 118stops the feeding action of the feeder 113. A suitable actuator button,not shown, is provided on the control unit 118 to operate theaccumulator door cylinder 870 when a weighted batch of articles hasaccumulated in the bucket 117.

Geometry of the Apparatus 100

Significant advantages are obtained from the type and arrangement ofcomponents employed in the apparatus 100.

Substantially all of the components are of modular configuration. Thesupply hopper 111, the vibratory conveyor 112, the vibratory feeder 113,the feeder hopper 114, the level switch assembly 115, the weighing unit116 the accumulator bucket 117, and the control unit 118 are each formseparate modules that can be removed and installed with ease tofacilitate servicing and assembly of the apparatus 100.

Still other advantages obtain from arrangement of components in theapparatus. Referring to FIG. 1, it will be seen that the supply hopper111, the vibratory conveyor 112, the feeder hopper 114 and theaccumulator bracket 117 are all arranged in series along an imaginaryline 900. As the line 900 passes from the vibratory conveyor 112 to thefeeder hopper, it is near the intersection of the side members 131, 132and the bracing members 134, 135. By this arrangement of components, theweight of the supply hopper 111 and the vibratory conveyor 112 togetherwith the weight of articles in the supply hopper 111 and in thevibratory conveyor 112 helps to counterbalance the weight of thedispenser 113 and the weighing unit 116 and such articles as are in thedispenser 113 and in the weighing unit 116.

The in-line arrangement of components permits the accumulator bucket 117to be positioned substantially forwardly of the frame side members 131,and forwardly of the stand 121. The substantial overhang thus providedfor the accumulator bucket 117 permits the bucket 117 to overhang largecontainers or other feeding or packaging apparatus without requiring aspecially configured chute to effect an interface with such equipment.

Operation of the Apparatus 100

In operation, articles to be dispensed in weighed batches are loadedinto the supply hopper 111. A desired weight of articles to be includedin each batch is set on the control unit 118. The level switch assembly115 is set to provide a desired level of articles in the feeder hopper114. Since the level of articles in the feeder hopper 114 is below thereference level set on the switch knob 325, the vibratory conveyor 112begins to operate to deliver articles into the feeder hopper 114. Thelevel switch 115 then regulates the operation of the vibratory conveyor112 to maintain the desired level articles in the feeder hopper 114.

The vibratory feeder 113 operates to deliver articles to both of thedischarge openings 225, 226. A "bucket empty" signal generated by theweighing unit 116 causes the bulk feed door 241 to open permittingarticles to discharge rapidly into the accumulator bucket 117. As theweight of articles in the bucket 117 begins to approach the desiredweight set on the control unit 118, the weighing unit signal reaches amagnitude that causes the door 241 to close. As a dribble feed ofarticles continues to discharge into the bucket 117 causing the weightof articles in the bucket 117 to more closely approach the desiredweight, the weighing unit signal reaches a magnitude that causes theoperation of the feeding unit 113 to be slowed to provide a slow singlefile feed of articles into the bucket 117. Once the desired weight isreached, the signal from the weighing unit 116 reaches a magnitude thatcauses feeder operation to stop. The bucket door 841 is then opened todischarge the weighed batch of articles, and the feeding cycle isrepeated to weigh a subsequent batch of articles for dispensing.

The Counting Unit Embodiment

An advantage of the described modular arrangement of components is thatit facilitates the substitution of a counting unit for the weighing unit116. As will be most easily appreciated by referring to FIGS. 28-38, theweighing unit module 116 can be replaced by a counting unit module 916to convert the apparatus from a batch weighing apparatus 100 to a batchcounting apparatus 910. Where appropriate, reference numerals from theembodiment of FIGS. 1-27 have been employed with the embodiment of FIGS.28-38 to indicate that many elements are common to both embodiments.Reference may be had to earlier portions of the specification for adescription of the common elements.

In a manner analogous to the weigher embodiment, the apparatus 910includes a base structure 110 which supports a supply hopper 111, avibratory conveyor 112, a vibratory feeder 113, and an accumulator unit916. The vibratory feeder 113 includes a feeder hopper 914. Theaccumulator unit 916 includes an accumulator bucket 917. In operation,articles to be dispensed are loaded into the supply hopper 111. Thevibratory conveyor 112 feeds articles from the supply hopper 111 intothe feeder hopper 914. The vibratory feeder 113 feed articles from thefeeder hopper 914 into the accumulator bucket 917. The operation of thevibratory conveyor 112 is controlled by a signal from a level switchassembly 115 to maintain a predetermined level of articles in the feederhopper 914.

The operation of the vibratory feeder 113 is controlled by a signal fromthe accumulator unit 916 to dispense a predetermined quantum of articlesinto the bucket 917. After the requisite quantum of articles hasaccumulated in the bucket 917, the articles are dispensed into thecontainer 102. A control unit 918 monitors operation of the accumulatorunit 916.

The Feeder Hopper 914

Referring to FIGS. 33 and 34, the feeder hopper 914 is a round,bowl-like structure having a bottom wall 1211 and an upstanding sidewall 1212. An annular rib 1213 projects upwardly into the hopper 914from the bottom wall 1211. Three bolt holes 1214 are formed through therib 1213. Threaded fasteners, not shown, extend through the holes 1214and mount the feeder hopper 914 on the armature 205.

The hopper side wall 1212 forms a spiral ramp 1221 that extendscircumferentially inside the hopper 914. The ramp 1221 has a lower end1222 that extends in the same plane as the bottom wall 1211. From thelower end 1222, the ramp 1221 extends upwardly at a small, uniform angleof inclination to an upper end 1223. When the feeder armature 205 isvibrated, articles in the feeder hopper 914 will move upwardly along theramp 1221 from the lower end 1222 toward the upper end 1223.

Three wiper blade assemblies 1230, 1240, 1250 are provided at spacedlocations along the ramp 1221 to limit the depth of flow of articlesalong the ramp 1221. The blade assemblies 1230, 1240, 1250 include blademembers 1231, 1241, 1251 having outer ends 1232, 1242, 1252 inengagement with the side wall 1212 and having inner ends 1233, 1243,1253 extending across the ramp 1221 at selected heights above the floorof the ramp 1221. Vertically extending slots 1234, 1244, 1254 are formedthrough the hopper side wall 1212 adjacent the outer ends 1232, 1242,1252. Threaded fasteners 1235, 1245, 1255 are secured to the outer ends1232, 1242, 1252 and extend through the slots 1234, 1244, 1254. Knurledthumb nuts 1236, 1246, 1256 are threaded onto the fasteners 1235, 1245,1255 and clamp the blade members 1231, 1241, 1251 in position on thehopper 914.

An additional article flow regulating assembly 1280 is positioned at theupper end 1223 of the ramp 1221. The regulating device 1280 includes amovable gating plate 1281 which can be positioned to selectivelyincrease or decrease the width of the ramp 1221 in the region of theassembly 1280. The gating plate 1281 extends through a slot 1282 formedin the hopper side wall 1212. The gating plate 1281 has a curved innerend 1283. The position of the curved inner end 1283 determines theeffective width of the ramp 1221 provided by the gating plate 1281. Anarrower ramp width, as provided by the plate 1281, will permit a lessernumber of articles to flow across the gating plate 1281 than will awider ramp width. The right end of the gating plate 1281, as viewed inFIG. 33, defines a discharge station 1290 through which articlesdischarging from the feeder hopper 914 pass on their way toward theaccumulator bucket 917.

A knurled thumb screw 1287 is threaded through a hole 1288 formed in thegating plate 1281 and engages a hopper side wall formation 1283 to clampthe gating plate 1281 in position on the hopper 914. The gating plate1281 is easily repositioned in the slot 1282 once the thumb screw 1287has been loosened.

The Accumulator Unit 916

Referring to FIG. 30, an accumulator unit support bracket 1360 ismounted atop the feeder support plate 137. The bracket 1360 extendsforwardly of the support plate 137 and supports the accumulator unit916. A vertically extending mounting rod 1361 is rigidly supported bythe bracket 1360 and depends forwardly of the feeder and feeder hopper113, 914.

Referring to FIGS. 35 and 36, the accumulator unit 916 includes a countsignalling unit 1370 supported by a bracket assembly 1371 on the rod1361. The count signalling unit is prefereably of the type described inthe referenced Counting Head Patent.

The bracket assembly 1371 includes an assembly of members 1375, 1376,1377 which are adjustable to position the count signalling assembly 1370immediately adjacent the discharge station of the feeder hopper 914.

The Accumulator Bucket 917

Referring to FIGS. 35-38, the accumulator bucket 917 is adjustablysupported by a bracket assembly 1400 on the mounting rod 1361. Thebucket 917 is generally rectangular in cross section and has foursidewalls 1401, 1402, 1403, 1404. Referring to FIG. 38, the sidewall1403 has a lower portion 1405 which inclines inwardly toward the wall1402. A discharge opening 1406 is defined between the wall portion 1405and the wall 1402.

A pivotally mounted door 1410 is provided to selectively open and closethe opening 1406. Threaded fasteners 1411 carry bushings 1412, extendthrough holes formed in the sidewalls 1401, 1404, and are threaded intoholes formed in the door 1410 to pivotally mount the door 1410 below theopening 1406. A tension coil spring 1415 has its opposite ends connectedto the door 1410 and to the wall portion 1405 to bias the door 1410toward an open position.

A pneumatic cylinder 1420 is mounted on the wall portion 1405. Thecylinder 1420 has an extensible piston rod 1421. The piston rod 1421connects with the door 1410 and is operative when extended, as shown inFIG. 38, to close the door 1410 in opposition to the action of thespring 1415. When the piston rod 1421 is retracted, the door 1410 pivotsto an open position.

The Control Unit 918

The control unit 918 is of the type described in the referencedDispenser Patent and governs the operation of the vibratory feeder 113in response to a signal from the count signalling unit 1370. Inoperation, the control unit 918 slows the feeding action of the feeder113 as the count of articles accumulated in the bucket 917 approaches apredetermined count which has been set on the control unit 918. When thecount sensed by the signalling unit 1370 equals the predetermined count,the control unit 918 stops the feeding action of the feeder 113. Asuitable actuator button, not shown, is provided on the control unit 918to operate the accumulator door cylinder 1420 when a counted batch ofarticles has accumulated in the bucket 917.

Operation of the Apparatus 910

In operation, articles to be dispensed in counted batches are loadedinto the supply hopper 111. A desired count of articles to be includedin each batch is set on the control unit 918. The level switch assembly115 is set to provide a desired level of articles in the feeder hopper914. Since the level of articles in the feeder hopper 914 is below thereference level set on the switch knob 325, the vibratory conveyor 112begins to operate to deliver articles into the feeder hopper 914. Thelevel switch 115 then regulates the operation of the vibratory conveyor112 to maintain the desired level of articles in the feeder hopper 914.

The vibratory feeder 113 operates to discharge articles past thecounting unit 916 into the accumulator bucket 917. A "zero count" signalgenerated initially by the counting unit 916 causes the vibratory feeder113 to operate at maximum feed velocity. As the count of articles in thebucket 917 approaches the desired count set on the control unit 918,feeder hopper drive speed is reduced to provide a slow, single filefeeding of articles past the counting unit 916. Once the desired countis reached, the feeder drive operation is stopped and the bucket door1410 is opened to discharge the counted batch of articles. The feedingcycle is then repeated to count a subsequent batch of articles fordispensing.

Although the invention has been described in its preferred form with acertain degree of particularity, it is understood that the presentdisclosure of the preferred form has been made only by way of exampleand that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted to withoutdeparting from the spirit and the scope of the invention as hereinafterclaimed.

What is claimed is:
 1. A compact freestanding dispensing apparatus, fordisposition on a support which can be small relative to the overall sizeof the apparatus, the apparatus being adapted to overhang a collectionreceptacle located adjacent such support to dispense articles into thecollection receptacle, comprising:(a) a frame structure having aninclined upwardly extending base portion and a supporting portion, saidbase portion including a lower region and an upper region, saidsupporting portion extending laterally from the upper region of saidbase portion such that said frame structure when viewed from one sidehas substantially the configuration of the numeral "7"; (b) a supplyhopper and a conveyor supported on the upper region of the base portion,and a vibratory feeder supported from said supporting portion; (c) saidsupply hopper having its center of gravity over said base portion andbeing operable to receive articles to be dispensed and to feed sucharticles to said conveyor; (d) said conveyor having its center ofgravity over said base portion and being operable to convey articlesfrom said supply hopper to said feeder hopper; (e) said vibratory feedercomprising a vibratory motor drive assembly and a recirculating bowlfeeder hopper including an article discharge station, said feederreceiving articles from said conveyor and conveying them atsubstantially controlled feed rates to said article discharge station,said vibratory motor drive assembly being supported by said supportingportion and in turn supporting said feeder hopper with said motor driveassembly being disposed within said feeder hopper and said feeder hopperbeing supported in communication with said discharge section of saidconveyor to receive articles therefrom, said article discharge stationbeing displaced from the upper region of said base portion beyond thelower region of said base portion and overhanging the collectionreceptacle when in use; (f) said supply hopper, said conveyor, and saidfeeder hopper being positioned in series along an imaginary line whichinclines downwardly as it extends from said supply hopper through saidconveyor to said feeder hopper; (g) said imaginary line passing near thejuncture of the base and supporting portions as it passes from theconveyor to the feeder hopper; (h) means including an accumulatorreceptacle positioned below the discharge station to receive, collect,and discharge articles which have passed through said discharge station;and (i) the center of gravity of said free standing dispensing apparatusalways being disposed over the lower region of said base portionirrespective of the number of articles supported in the apparatus,whereby said freestanding dispensing apparatus rests stably upon thesupport while articles may be directly discharged from said overhangingaccumulator into the underlying collection receptacle when suchreceptacle is in use.
 2. A compact freestanding dispensing apparatusconstructed for disposition on a horizontal supporting surface which canbe small relative to the overall size of the apparatus, the apparatusenabled to overhang a collection receptacle located adjacent thehorizontal supporting surface to dispense articles into the collectionreceptacle, comprising:(a) a frame structure including a base portionand a supporting portion, said base portion including a lower region andan upper region, said lower region adapted to be disposed on thesupporting surface; (b) said base portion being inclined upwardly fromsaid lower region to said upper region such that said upper region islaterally displaced with respect to said lower region in a firstdirection; (c) said supporting portion being carried by said baseportion at said upper region and extending in a second directionopposite to said first direction; (d) a supply hopper for storing bulkquantities of articles to be dispensed, said supply hopper beingsupported by said base portion at said upper region with its center ofgravity being disposed over said lower region of said base portion; (e)a conveyor communicating with said supply hopper for transportingarticles discharged from the supply hopper, said conveyor also beingsupported by said base portion at said upper region with its center ofgravity being disposed over said lower end region of said base portion;(f) a vibratory feeder comprising a vibratory motor drive assembly and arecirculating bowl feeder hopper including an article discharge station,said feeder receiving articles from said conveyor and conveying them atcontrolled feed rates to said article discharge station, said vibratorymotor drive assembly being supported by said supporting portion and inturn supporting said feeder hopper with said vibratory motor driveassembly being disposed within said feeder hopper and said feeder hopperbeing supported in communication with said discharge section of saidconveyor to receive articles therefrom, said article discharge stationbeing displaced in said second direction from said conveyor beyond thelower region of said base portion and directly overhanging thecollection receptacle when in use; (g) the conveyor including anelongated trough having a bottom wall and upstanding sidewalls, thesupply hopper having sidewalls which depend into the conveyor trough tochannel articles from the supply hopper into the conveyor trough, theconveyor trough sidewalls and the supply hopper sidewalls havingoverlapping sidewall portions; and (h) a pair of aligned doors formedone on the supply hopper and the other on the conveyor trough in theregion of the overlapping sidewall portions to selectively provideaccess by an operator to the region enclosed by the overlapping sidewallportions, whereby articles can be easily removed from such enclosedregion without having to feed such articles to the feeder.
 3. Theapparatus of claim 2 wherein an adjustable gate structure is carried onone of the supply hopper sidewalls and depends into the conveyor troughto assist in regulating the flow of articles along the conveyor trough.4. The dispensing apparatus of claim 2 wherein the feeder hopperincludes a bottom wall and a ramp disposed peripherally of the bottomwall and extending upwardly from the bottom wall to the articledischarge station, and wherein said vibratory motor drive assembly isattached to said bottom wall whereby articles disposed in said hopperaround said vibratory motor drive assembly can be transported upwardlyalong said ramp at controlled feed rates to said article dischargestation by vibratory motion imparted to said hopper by said vibratorymotor drive assembly.
 5. The apparatus of claim 2 wherein the vibratorybowl feeder further comprises:(a) a bowl-shaped feeder hopper having abase portion, a sidewall, and a ramp extending upwardly from the baseportion; (b) a first discharge opening communicating with the baseportion for discharging a relatively large quantity of articles in agiven time interval; (c) a second discharge opening communicating withthe ramp for discharging a relatively small quantity of articles in suchgiven time period; and, (d) flow restriction means for selectivelyrestricting the flow of articles discharging through the first opening.6. The apparatus of claim 2 wherein:(a) a collecting and dispensingmeans is positioned below the discharge station and carried by the basestructure for collecting and dispensing articles which have passedthrough the discharge station, the collecting and dispensing meansincluding an accumulator receptacle; (b) a weighing means for weighingarticles passing through the discharge station is carried by the basestructure; (c) the feeder hopper has an upstanding perimetricallyextending sidewall, a first discharge opening communicating with a baseportion, a ramp extending upwardly from the base portion and a seconddischarge opening communicating with the ramp, the first and seconddischarge openings being located near each other and at the dischargestation; and (d) flow restriction means for selectively restricting theflow of articles discharging through the first opening.
 7. A compactfreestanding dispensing apparatus constructed for disposition on arelatively small support as compared to the overall size of theapparatus, the apparatus being adapted to overhang a collectionreceptacle located adjacent the support to dispense metered amounts ofarticles into such collection receptacle, comprising:(a) a framestructure including a base portion and a supporting portion, said baseportion including a lower region and an upper region, said lower regionbeing adapted to be disposed on such support; (b) said base portionbeing inclined upwardly from said lower region to said upper region suchthat said upper region is laterally displaced with respect to said lowerregion in a first direction; (c) said supporting portion being attachedto said upper region of said base portion and extending in a seconddirection opposite to said first direction; (d) a supply hopper forstoring quantities of articles to be dispensed, said supply hopperincluding an opening for receiving quantities of articles and an openingfor discharging those articles, said supply hopper being supported bysaid upper region of said base portion with the center of gravity ofsaid supply hopper being disposed over said lower region of said baseportion; (e) a conveyor for transporting articles discharged from thesupply hopper, said conveyor having spaced receiving and dischargesections, said receiving section being disposed under said supply hopperdischarge opening, said conveyor extending in said second direction fromsaid receiving section to said discharge section, said conveyor alsobeing supported by said upper region of said base portion, with thecenter of gravity of said conveyor being disposed over said lower endregion of said base portion; (f) a vibratory feeder comprising avibratory motor drive assembly and a recirculating bowl feeder hopperincluding an article discharge station, said feeder receiving articlesfrom said conveyor and delivering them at controlled feed rates to saidarticle discharge station, said vibratory motor drive assembly beingsupported by said supporting portion and in turn supporting said feederhopper with said vibratory motor drive assembly being disposed at leastin part within said feeder hopper and said feeder hopper being supportedin communication with said discharge section of said conveyor to receivearticles therefrom, said article discharge station being displaced insaid second direction from said conveyor beyond the lower region of saidbase portion for directly overhanging a collection receptacle when inuse; (g) an accumulator connected to the frame structure and includingan article discharge means, the accumulator being positioned above suchcollection receptacle when the accumulator and receptacle are in use,the accumulator being positioned and adapted to receive and collectarticles emitted through said discharge station after they have passedalong a flow path from the discharge station to the accumulator, theaccumulator also being adapted to discharge such articles into thecollection receptacle; and (h) the center of gravity of said freestanding dispensing apparatus being disposed over the lower region ofsaid base portion irrespective of the number of articles supported inthe apparatus, whereby said freestanding dispensing apparatus alwaysrests stably upon said support without the need for anchoring whilearticles may be directly discharged from said overhanging accumulatorinto the underlying collection receptacle when such receptacle is inuse.
 8. The apparatus of claim 7 wherein said supply hopper, saidconveyor, said vibratory feeder, and said accumulator are arranged inseries substantially along an imaginary line which inclines downwardlyfrom a horizontal plane as it extends in said second direction from saidsupply hopper through said conveyor and through said vibratory motordrive assembly and said feeder hopper to said accumulator.
 9. Theapparatus of claim 8 wherein said imaginary line in crossing from saidconveyor to said vibratory motor drive assembly and said feeder hopperpasses near the juncture of said supporting and base portions of saidframe structure.
 10. The apparatus of claim 7 wherein each of saidsupply hopper, said conveyor, said vibratory motor drive assembly, saidfeeder hopper, and said accumulator comprise substantially individualmodular units independently secured to the frame structure to facilitatetheir removal and installation for servicing and assembly.
 11. Theapparatus of claim 7 further comprising quantifying means connected tothe frame structure and disposed along the flow path for countingindividual articles as they pass through said discharge station.
 12. Theapparatus of claim 11 wherein the quantifying means comprises countingmeans disposed immediately adjacent the article discharge station sothat articles discharged into the accumulator are counted immediatelyupon such discharge and the quantity of articles discharged can beaccurately controlled.
 13. The dispensing apparatus of claim 7, andfurther comprising:(a) drive means for driving said conveyor, and (b)control means for providing an output signal which selectively controlsstarting and stopping of the drive means in response to the level ofarticles sensed in the feeder hopper to maintain a predetermined levelof articles therein, said control means including:(i) sensor means forsensing the level of articles in the feeder hopper and for providing aninput signal representative of the sensed level of articles in thefeeder hopper; (ii) a manually operated control for providing areference signal representative of a desired predetermined level ofarticles to be maintained in the feeder hopper; and (iii) comparisonmeans connected to the sensor means and to the control for receiving andcomparing the input and reference signals and for providing an outputsignal indicative of when the actual sensed level of articles is aboveand below the desired predetermined level.
 14. The apparatus of claim 13wherein the sensor means includes an arm pivotally mounted to engageupper surfaces of articles in the feeder hopper, and a sensor transducerconnected to the arm to provide the input signal with a valverepresentative of the position of the arm.
 15. The apparatus of claim 13wherein the control includes a potentiometer having a rotatable stem anda knob for rotating the potentiometer stem to adjust the resistance ofthe potentiometer to a value indicative of the desired predeterminedlevel.
 16. The apparatus of claim 13 wherein the comparison meansincludes an operational amplifier for providing a higher level outputsignal when the sensed actual level of articles in the feeder hopper isbelow the desired predetermined level than when the sensed actual levelis at or above the predetermined level.
 17. The apparatus of claim 16additionally including light emitting signal means connected to theoperational amplifier for providing a visual indication to an operatorwhen the sensed actual level is below the desired predetermined level.18. The apparatus of claim 7 further comprising weighing means carriedby the frame structure, the weighing means supporting the accumulator.19. The apparatus of claim 7 wherein the feeder hopper includes a pairof discharge openings at the discharge station and gating means forselectively opening and closing one of the discharge openings.
 20. Theapparatus of claim 19 wherein the discharge opening associated with thegating means extends in a substantially vertical plane, and the gatingmeans includes a substantially vertically movable door for opening andclosing the associated opening.
 21. The apparatus of claim 20 whereinthe door moves upwardly to close the associated opening and movesdownwardly to open the associated opening.
 22. The apparatus of claim 7wherein the accumulator includes:(a) weighing means carried on the framestructure including:(i) a housing structure positioned forwardly of andin the same horizontal plane with portions of the feeder; (ii) anarmature movably supported in the housing structure; (iii)electrically-operated armature positioning means carried within thehousing structure for applying such forces to the armature as are neededto maintain the armature at a predetermined position; (iv) signallingmeans operably connected to the armature for generating an electricalsignal representing the magnitude of the forces applied by the armaturepositioning means to the armature; (v) an accumulator receptaclesupported by the armature and positioned to receive and collect articleswhich pass through the discharge station; and (b) the weighing meansbeing releasably secured to the frame structure as a self-containedmodule to facilitate its removal and installation for servicing andassembly.